[MOS] MOS location

[Zina Queen]

MOS wil be held Grier Room 34-401A


Seminar on
Modern Optics and Spectroscopy


Gabriel Popescu, MIT

Quantitative phase imaging: watching cells waltz

October 3, 2006

12:00 noon - 1:00 p.m.

Abstract:

Phase contrast (PC) and differential interference contrast (DIC) 
microscopy have been used for several decades to infer morphometric 
features of live cells without the need for exogenous contrast 
agents. These techniques transfer the information encoded by the 
phase of the imaging field into the intensity distribution of the 
final image. Thus, the optical phase shift through a given sample can 
be regarded as a powerful endogenous contrast agent, as it contains 
information about both the thickness and refractive index of the 
sample. However, both PC and DIC are qualitative in terms of optical 
path-length measurement, i.e. the relationship between the irradiance 
and phase of the image field is generally nonlinear. Quantifying the 
optical phase shifts associated with biological structures gives 
access to information about morphology and dynamics at the nanometer 
scale. Over the past decade, the development of quantitative phase 
imaging techniques has received increased scientific interest. At the 
MIT Spectroscopy Laboratory, we have developed several 
interferometric phase imaging techniques, which are characterized by 
sub-nanometer optical path-length sensitivity over broad time scales, 
i.e. milliseconds to days. These novel optical methods offer a fresh 
look at basic cell biophysics, such as cell motility, cell growth and 
membrane fluctuations. Furthermore, this type of investigation may 
provide a better understanding of diseases such as malaria and sickle 
cell anemia.
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